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Megawite

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About MegawiteHide

Helen D. Megaw
Formula:
CaSnO3
Colour:
Pale yellowish brown, pale yellow to colourless
Lustre:
Vitreous
Specific Gravity:
5.06 (Calculated)
Crystal System:
Orthorhombic
Name:
It is named in honour of the British crystallographer Helen Dick Megaw (1 June 1907, Dublin, Ireland - 26 February 2002, Ballycastle, Northern Ireland) who made significant contributions to our understanding of the structure and properties of natural and synthetic perovskites. In 1989, Megaw became the first woman to receive the Roebling Medal of the Mineralogical Society of America.
Isostructural with:
Perovskite Group. The Sn analogue of perovskite and lakargiite.
Chemically related to burtite.


Classification of MegawiteHide

Approved
Approval Year:
2010
4.CC.30

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
C : Metal: Oxygen = 2: 3,3: 5, and similar
C : With large and medium-sized cations

Physical Properties of MegawiteHide

Vitreous
Transparency:
Transparent
Colour:
Pale yellowish brown, pale yellow to colourless
Streak:
White
Cleavage:
Distinct/Good
on {110} and {001}
Density:
5.06 g/cm3 (Calculated)

Optical Data of MegawiteHide

Type:
Biaxial
RI values:
n = 1.89
Max Birefringence:
δ = 0.000
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Very High

Chemical Properties of MegawiteHide

Formula:
CaSnO3

Crystallography of MegawiteHide

Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:
Pban
Cell Parameters:
a = 5.56(3) Å, b = 5.71(3) Å, c = 7.943(3) Å
Ratio:
a:b:c = 0.974 : 1 : 1.391
Unit Cell V:
252.17 ų (Calculated from Unit Cell)
Z:
4

X-Ray Powder DiffractionHide

Powder Diffraction Data:
d-spacingIntensity
3.984 (52)
3.970 (19)
2.855 (43)
2.812 (100)
2.780 (19)
1.992 (13)
1.985 (13)
1.640 (13)

Type Occurrence of MegawiteHide

General Appearance of Type Material:
Either pseudo-cubic or pseudo-cuboctahedral crystals do not exceed 15 µm in size and usually occur as inclusions in spurrite (xenolith No. 1). Megawite forms rims on µm-sized lakargiite crystals in larnite-cuspidine zones in skarns which contain abundant
Place of Conservation of Type Material:
Mineralogical Museum of Wrocław University, Poland under accession number MMUWrII16 717 and the Fersman Mineralogical Museum, Moscow, Russia under accession number4021/1.
Geological Setting of Type Material:
It was found in the spurrite zone of skarned xenolith no. 1 (20-25 m in size) in ignimbrite.
Associated Minerals at Type Locality:

Synonyms of MegawiteHide

Relationship of Megawite to other SpeciesHide

Other Members of this group:
BarioperovskiteBaTiO3Orth. mm2 : Amm2
Isolueshite(Na,La)NbO3Iso. m3m (4/m 3 2/m) : Pm3m
Loparite-(Ce)(Na,REE)Ti2O6
LueshiteNaNbO3Orth. mmm (2/m 2/m 2/m)
MacedonitePbTiO3Tet. 4/mmm (4/m 2/m 2/m) : P4/nmm
PerovskiteCaTiO3Orth. mmm (2/m 2/m 2/m) : Pnma
TausoniteSrTiO3Iso. 4 3m

Related Minerals - Nickel-Strunz GroupingHide

4.CC.AllendeiteSc4Zr3O12Trig. 3 : R3
4.CC.Yttriaite-(Y)Y2O3Iso.
4.CC.05ChrombismiteBi16CrO27Tet.
4.CC.10FreudenbergiteNa2(Ti,Fe)8O16Mon.
4.CC.15GrossiteCaAl4O7Mon. 2/m : B2/b
4.CC.20ChlormayeniteCa12Al14O32[◻4Cl2]Iso. 4 3m : I4 3d
4.CC.25YafsoaniteCa3Zn3(TeO6)2Iso. m3 (2/m 3)
4.CC.30LatrappiteCa2NbFe3+O6Orth. mmm (2/m 2/m 2/m) : Pnma
4.CC.30LueshiteNaNbO3Orth. mmm (2/m 2/m 2/m)
4.CC.30NatroniobiteNaNbO3Mon.
4.CC.30PerovskiteCaTiO3Orth. mmm (2/m 2/m 2/m) : Pnma
4.CC.30BarioperovskiteBaTiO3Orth. mm2 : Amm2
4.CC.30LakargiiteCa(Zr,Sn,Ti)O3Orth. mmm (2/m 2/m 2/m) : Pnma
4.CC.35Loparite-(Ce)(Na,REE)Ti2O6
4.CC.35MacedonitePbTiO3Tet. 4/mmm (4/m 2/m 2/m) : P4/nmm
4.CC.35TausoniteSrTiO3Iso. 4 3m
4.CC.35Isolueshite(Na,La)NbO3Iso. m3m (4/m 3 2/m) : Pm3m
4.CC.40CrichtoniteSr(Mn,Y,U)Fe2(Ti,Fe,Cr,V)18(O,OH)38Trig. 3 : R3
4.CC.40Davidite-(Ce)(Ce,La)(Y,U,Fe)(Ti,Fe)20(O,OH)38Trig. 3 : R3
4.CC.40Davidite-(La)(La,Ce)(Y,U,Fe)(Ti,Fe)20(O,OH)38Trig.
4.CC.40Davidite-(Y)(La,Ce,Na,Ca,Pb)(Y,Fe2+,◻)(Fe2+,Mn2+)2(Ti,Fe3+,Nb,Zr)18O38 (hypothetical)Trig.
4.CC.40LandauiteNaMnZn2(Ti,Fe)6Ti12O38Trig. 3 : R3
4.CC.40Lindsleyite(Ba,Sr)(Zr,Ca)(Fe,Mg)2(Ti,Cr,Fe)18O38Trig.
4.CC.40Loveringite(Ca,Ce,La)(Zr,Fe)(Mg,Fe)2(Ti,Fe,Cr,Al)18O38Trig.
4.CC.40Mathiasite(K, Ba, Sr)(Zr, Fe)(Mg,Fe)2 (Ti,Cr,Fe)18O38Trig.
4.CC.40SenaitePb(Mn,Y,U)(Fe,Zn)2(Ti,Fe,Cr,V)18(O,OH)38Trig.
4.CC.40Dessauite-(Y)(Sr,Pb)(Y,U)(Ti,Fe3+)20O38Trig. 3 : R3
4.CC.40Cleusonite(Pb,Sr)(U4+,U6+)(Fe2+,Zn)2(Ti,Fe2+,Fe3+)18(O,OH)38Trig. 3 : R3
4.CC.40Gramaccioliite-(Y)(Pb,Sr)(Y,Mn)Fe3+2(Ti,Fe3+)18O38Trig. 3
4.CC.45DiaoyudaoiteNaAl11O17Hex.
4.CC.45HawthorneiteBaMgTi3Cr4Fe2+2Fe3+2O19Hex. 6/mmm (6/m 2/m 2/m) : P63/mmc
4.CC.45Hibonite(Ca,Ce)(Al,Ti,Mg)12O19Hex.
4.CC.45LindqvistitePb2Mn2+Fe16O27Hex.
4.CC.45Magnetoplumbite(Pb,Mn)(Fe,Mn)12O19Hex.
4.CC.45PlumboferritePb2(Fe3+,Mn2+,Mg)11O19Trig. 3 2 : P3 1 2
4.CC.45YimengiteK(Cr,Ti,Fe,Mg)12O19Hex.
4.CC.45HaggertyiteBaFe2+4Fe3+2Ti5MgO19Hex. 6/mmm (6/m 2/m 2/m) : P63/mmc
4.CC.45NežilovitePbZn2Mn4+2Fe3+8O19Hex. 6/mmm (6/m 2/m 2/m) : P63/mmc
4.CC.45BatiferriteBaTi2Fe3+8Fe2+2O19Hex.
4.CC.45Hibonite-(Fe)(Fe,Mg)Al12O19Hex. 6/mmm (6/m 2/m 2/m) : P63/mmc
4.CC.45BarioferriteBaFe3+12O19Hex. 6/mmm (6/m 2/m 2/m) : P63/mmc
4.CC.50Jeppeite(K,Ba)2(Ti,Fe)6O13Mon.
4.CC.55ZenzénitePb3Fe4Mn3O15Hex.
4.CC.60Mengxianminite (of Huang et al.)(Ca,Na)3(Fe,Mn)2Mg2(Sn,Zn)5Al8O29

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for MegawiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Galuskin, E.V., Galuskina, I.O., Gazeev, V.M., Dzierżanowski, P., Prusik, K., Pertsev, N.N., Zadov, A.E. & Gurbanov, A.G. (2010): Megawite CaSnO3 - a new mineral of the perowskite group. 20th General Meeting of the IMA (IMA2010), Budapest, Hungary, August 21-27, CD of Abstracts, p. 444.
Galuskin, E.V., Galuskina, I.O., Gazeev, V.M., Dzierżanowski, P., Prusik, K., Pertsev, N.N., Zadov, A.E., Bailau, R. & Gurbanov, A.G. (2011): Megawite, CaSnO3: a new perovskite-group mineral from skarns of the Upper Chegem caldera, Kabardino-Balkaria, Northern Caucasus, Russia. Mineralogical Magazine, 75, 2563-2572.

Internet Links for MegawiteHide

Localities for MegawiteHide

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
Russia (TL)
 
  • Northern Caucasus Region
    • Kabardino-Balkarian Republic
      • Baksan Valley
        • Upper Chegem volcanic caldera (Verkhnechegemskaya caldera)
          • Lakargi Mt.
Galuskin, E.V., Galuskina, I.O., Gazeev, V.M., Dzierżanowski, P., Prusik, K., Pertsev, N.N., Zadov, A.E., Bailau, R. & Gurbanov, A.G. (2011): Megawite, CaSnO3: a new perovskite-group mineral from skarns of the Upper Chegem caldera, Kabardino-Balkaria, Northern Caucasus, Russia. Mineralogical Magazine, 75, 2563-2572.
Mineral and/or Locality  
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